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Tytuł:
Optimization of a dual-slot waveguide for a refractive index biosensor
Autorzy:
Sahu, S.
Ali, J.
Singh, G.
Powiązania:
https://bibliotekanauki.pl/articles/173377.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
biosensor
evanescent field
eigenmode
dispersion
Opis:
The present article illustrates the modeling and optimization of a dual-slot waveguide for the application of a refractive index biosensor. The nanometer scale waveguide structure uses the silicon-on-insulator platform for the consideration of higher sensitivity and compactness of a resonator biosensor. The modal analysis is performed using the finite difference method based on full vector eigenmode calculation. The maximum field penetration in the lower index region is found for the quasi-TE mode. The sensitivity is maximized through the optimization of the waveguide dimension by relating effective refractive index with the dispersion of a waveguide. The biosensor showed the maximum calculated sensitivity of 461.327 nm/RIU and a limit-of-detection of 2.601 × 10–6 RIU (where RIU denotes refractive index unit).
Źródło:
Optica Applicata; 2018, 48, 1; 161-167
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of transient natural convective flow of a nanofluid in a vertical tube
Autorzy:
Jha, Basant K.
Chitumu, Ali J.
Oni, Michael O.
Powiązania:
https://bibliotekanauki.pl/articles/1839829.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
nanociecze
naturalna konwekcja
wymiana ciepła
nanofluid
transient
natural convection
heat transfer
vertical tube
Opis:
An analysis into the transient natural convective flow of a nanofluid in a vertical tube is made. The governing equations of momentum, heat transfer and nanoparticle volume fraction are deduced, and the influence of the thermophoresis parameter and Brownian motion is incorporated. By direct integration and variation of the parameter, analytical solutions are obtained for flow formation and heat/mass transfer at steady-state. On the other hand, due to the complexity of same problem at transient state, a numerical solution is used to solve the discretized equations of motion using the implicit finite difference technique. The influence of the thermophoresis parameter and Brownian motion is noted and well discussed. For accuracy check, a numerical comparison is made between the steady state and transient state solution at large time; this comparison gives an excellent agreement. The role of various principal parameters on velocity profile, temperature, concentration of nanoparticles, Sherwood and Nusselt numbers are presented graphically and well discussed. It is noted that the buoyancy ratio decreases the fluid velocity significantly.
Źródło:
International Journal of Applied Mechanics and Engineering; 2021, 26, 2; 31-46
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of thermo-hydraulic performance of a solar air heater tube with modern obstacles
Autorzy:
Menni, Younes
Chamkha, Ali J.
Zidani, Chafika
Benyoucef, Boumédiène
Powiązania:
https://bibliotekanauki.pl/articles/240666.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
turbulence
heat transfer
friction loss
flow attack
solar air heater tube
Opis:
This paper presents a numerical analysis on turbulent flow and forced-convection characteristics of rectangular solar air heater tube fitted with staggered, transverse, V-shape, modern obstacles on the heated walls. Air, whose Prandtl number is 0.71, is the working fluid used, and the Reynolds number considered equal to 6×10 3. The governing flow equations are solved using a finite volume approach and the semi-implicit pressure linked equation (SIMPLE) algorithm. With regard to the flow characteristics, the quadratic upstream interpolation for convective kinetics differencing scheme (QUICK) was applied, and a second-order upwind scheme (SOU) was used for the pressure terms. The dynamic thermo-energy behavior of the V-shaped baffles with various flow attack angles, i.e., 50°, 60°, 70°, and 80° are simulated, analyzed, and compared with those of the conventional flat rectangular baffles with attack value of 90°. In all situations, the thermal transfer rate was found to be much larger than unity; its maximum value was around 3.143 for the flow attack angle of 90° and y = H/2.
Źródło:
Archives of Thermodynamics; 2020, 41, 3; 33-56
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and Characterization of a Novel Hyperbranched Polyester Polymers Using A2+B3 Monomers
Autorzy:
Al-Mutairi, Nabeel Hasan
Al-Zubiedy, Ali
Al-Zuhairi, Ali J
Powiązania:
https://bibliotekanauki.pl/articles/26081324.pdf
Data publikacji:
2023
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
hiperrozgałęziony poliester HBP
monomer A2+B3
polycondensation
1H-NMR
GPC
hyperbranched polyester HBP
A2+B3 monomer
Opis:
Compared to linear analogs, hyperbranched polymers (HBPs) have gotten much attention in the last decade because of their intrinsic globular topologies and distinctive features like low viscosity, high solubility, and a high degree of functionality. In this work, four types of hyperbranched polyester polymer HBPs have been synthesized using the A2+B3 polycondensation methodology. Firstly, the starting material B3 monomer (Pyrimidine-2,4,6-triol) has been synthesized using urea and malonic acid with the presence of sodium Na as the catalyst for the reaction. Secondly, four types of materials (tartaric acid TA, adipic acid AD, maleic acid MA, and phthalic anhydride PA) as A2 monomers were added to the starting material B3 monomer in an oil bath to prepare the four types of HBP. The chemical structure of HBPs was characterized by FTIR, and 1H-NMR. The molecular weight of the prepared HBPs was characterized by gel permeation chromatography GPC, and thermal properties were characterized by differential scanning calorimetry DSC and thermal gravimetric analysis TGA. FTIR results showed that there are new bands, such as C-O-C between A2 and B3 monomers, as indicated by 1H-NMR. In addition, GPC shows that the prepared polymers have a narrow molecular weight distribution with good thermal stability, as indicated by DSC and TGA.
Źródło:
Production Engineering Archives; 2023, 29, 1; 28--36
2353-5156
2353-7779
Pojawia się w:
Production Engineering Archives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis and optimization of a winglet sweep angle and winglet tip chord for improvement of aircraft flight performance
Autorzy:
Al-Khafaji, Ali J. Dawood
Panatov, Gennady S.
Boldyrev, Anton S.
Powiązania:
https://bibliotekanauki.pl/articles/2096195.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
lift
drag
lift coefficient
drag coefficient
aircraft wing
winglet
angle of attack
sweep angle
SOLIDWORKS
CFD
ANSYS FLUENT
współczynnik siły nośnej
współczynnik oporu
skrzydło samolotu
skrzydełko aerodynamiczne
kąt natarcia
SolidWorks
ANSYS Fluent
Opis:
In this paper, a study of the effect of winglet sweep angle and winglet tip chord of the aircraft wing on the aerodynamics performances and how to improve it are carried out, assuming Cant angle 60°, winglet height = 3.5 m, Toe angle = -5°, and Twist angle = +5°. Different sweep angles tested (-25°, -15°, 0°, +15°, +25°, +35°, and +45°) and winglet tip chord (0.25, 0.375, and 0.5 m). Four Angle of attack is presented (0°, 3°, 6°, and 9°). The aerodynamics properties of the wing were measured in terms of calculated lift to drag ratio to decide which wing has a high value of lift and lower drag. All models of a wing (eighty-four models) are drawn for 3D using the SOLIDWORKS program. Boeing 737-800 wing dimensions were used. All models of a wing were analyzed using ANSYS FLUENT. The results showed that sweep angle and winglet tip chord of the winglet by changing their configuration can improve aerodynamic performance for various attack angles. The maximum value of the lift to drag ratio was obtained with a sweep angle -15°, winglet tip chord 0.375m, and angle of attack 3°.
Źródło:
Diagnostyka; 2022, 23, 2; art. no. 2022210
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phytoextraction of Cr by maize (Zea mays L.) : the role of plant growth promoting endophyte and citric acid under polluted soil
Autorzy:
Ali, J.
Mahmood, T.
Hayat, K.
Afridi, M. S.
Ali, F.
Chaudhary, H. J.
Powiązania:
https://bibliotekanauki.pl/articles/204568.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
maize
phytoextraction
chromium
citric acid
Burkholderia vietnamiensis
Opis:
High chromium (Cr) toxicity has turned into a serious environmental concern. Cr contaminated agronomic soils negatively affect the growth and yield of crops. Current research was conducted to enhance the phytoextraction potential of maize by using Burkholderia vietnamiensis and citric acid (CA). Plants were subjected to three concentrations of Cr (0.86, 350, and 500 ppm). A pot experiment was conducted under greenhouse conditions with completely randomized design (CRD). After 72 days of experiment, plants were harvested to analyze the morphological and biochemical attributes of soil, bacteria and plant. Results revealed that plant fresh, dry biomass, root, shoot length and chlorophyll contents significantly increased by 56%, 50%, 58%, 78% and 60%, respectively, at 500 ppm Cr concentration in combine treatment of B. vietnamiensis and CA. Maize plants treated with both B. vietnamiensis and CA significantly increased the bioaccumulation (BA) of Cr up to 50% and translocation factor (TF) by 31%. Furthermore, superoxide dismutase (SOD), proline and peroxidase dismutase (POD) activities in leaves were markedly increased by 30%, 42% and 15%, respectively, when treated with CA. Current study reveals that exogenous co-application of B. vietnamiensis + CA enhance plant growth by alleviating heavy metal stress and accelerate the phytoextraction of Cr. Taking into account the heavy metal tolerance and accumulation capacity, Zea mays is suitable for phytoremediation of contaminated soils in combination with B. vietnamiensis and CA.
Źródło:
Archives of Environmental Protection; 2018, 44, 2; 73-82
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Designing Eight-port Antenna Array for Multi-Band MIMO Applications in 5G Smartphones
Autorzy:
Al-Azzawi, Zainab Faydhe
AbdulSattar, Rusul Khalid
Muhsin, Muhannad Y.
Azeez, Mohammed Abdulrazzaq
Salim, Ali J.
Ali, Jawad K
Powiązania:
https://bibliotekanauki.pl/articles/27312953.pdf
Data publikacji:
2023
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
5G communication
compact MIMO antenna
decoupling techniques
fractal geometry
multi-band antenna
Opis:
This article introduces a dual-functional low-profile compact multiple input multiple output (MIMO) antenna array for multi-band communication in 5G smartphones. The proposed eight elements of the antenna array form two different 4 ×4 MIMO systems. The first four elements are placed at the four mobile corners and operate in a single band of 3. 445– 3. 885 GHz for 5G n77 and n 78 applications. The other system, in which four antennas are positioned in the middle of the terminal board, supports two wide bands of 1 . 684– 2. 300 GHz and 4. 432 – 5. 638 for n 2, n 3, n 39, n 65, n 66, n 79 , and WLAN applications. The second iteration of a modified Peano-type fractal geometry served as the design foundation for the proposed antenna element. The system’s ground plane design is based on self-isolated and spatial diversity methods. The single-band MIMO system’s isolation is better than 23 dB. In the dual-band MIMO system that is based on self-isolation, isolation equals approximately 16 dB in the higher band and 10 dB in the lower band. To evaluate performance, radiation-related and total antenna efficiencies, scattering parameters and gains were investigated. Additionally, ECCs have been considered to evaluate MIMO performance. According to the results, such design constitutes a valuable option for MIMO applications in 5G smartphones.
Źródło:
Journal of Telecommunications and Information Technology; 2023, 4; 18--24
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of artificial coastal protection structures on Ascidians settlement along the Tamil Nadu coast, India
Autorzy:
Jebakumar, J.P.P.
Nandhagopal, G.
Babu, B.R.
Ragumaran, S.
Ramakritinan, C.M.
Ali, A.J.
Arshan, M.K.
Ravichandran, V.
Powiązania:
https://bibliotekanauki.pl/articles/48441.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
artificial structure
urban sprawl
landscape change
non-native species
Tamil Nadu coast
India
Źródło:
Oceanologia; 2019, 61, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance evaluation of ZVS/ZCS high efficiency AC/DC converter for high power applications
Autorzy:
Ali, A.
Chuanwen, J.
Khan, M. M.
Habib, S.
Ali, Y.
Powiązania:
https://bibliotekanauki.pl/articles/200472.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
switching losses
zero current switching
zero voltage switching
power quality
reverse recovery loss
Opis:
The increased power density, reduced switching losses with minimum electromagnetic interference (EMI), and high efficiency are essential requirements of power converters. To achieve these characteristics, soft power converters employing soft switching techniques are indispensable. In this paper, a ZCS/ZVS PWM AC/DC converter topology has been emphasized, which finds applications in high power systems such as automobile battery charging and renewable energy systems. This converter scheme maintains zero current and zero voltage switching conditions at turn on and turn off moments of semiconductor switches, respectively and soft operation of rectifier diodes that lead to negligible switching and diode reverse recovery losses. Moreover, it improves power quality and presents high input power factor, low total harmonic distortion of the input current (THDI ) and improved efficiency. The validity of theoretical analysis of the proposed converter has been carried out experimentally on a 10 kW laboratory prototype. Experimental results prove that the soft switching operation of the semiconductor switches and diodes is maintained at 98.6% rated load efficiency. In addition, the performance evaluation has been performed by comparative analysis of the proposed converter with some prior art high power AC/DC converters. Efficiencies of the proposed and prior art high power topologies have been determined for different load conditions. The highest efficiency, power factor and lower THDI of the proposed converter topology complies with international standards.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 4; 793-807
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancement of Some Mechanical Properties of Polyethylene Glycol by Adding Carboxymethyl Cellulose as a Blends and Applied in Wood Glue
Autorzy:
Obeid, Karrar Abd-Ali
Al-Bermany, Abdul-Kareem J.
Habeeb, Majeed Ali
Powiązania:
https://bibliotekanauki.pl/articles/1193936.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Acoustical Properties
CMC
Carboxymethyl Cellulose
PEG
Polyethylene Glycol
Ultrasonic Technique
Wood Glue
Opis:
The (PEG/CMC) blends were prepared by liquids mixing method, the appropriate concentrations of PEG were (0.1-0.2 to 0.8 g/mL)% are dissolved in (500 mL) of distilled water under stirring without heat for (20 min.) then added the CMC with two weights (0.25 and 0.5) g for each PEG concentrates at (288 K). In order to evaluate the mechanical properties of (PEG/CMC) blends the ultrasonic measurements were performed at these samples, these properties are ultrasonic velocity, compressibility, acoustic impedance and bulk modulus, were made at fixed frequency (f = 25 kHz), another acoustic mechanical properties were measured and calculated at a same time such as the ultrasonic wave amplitude absorption by using oscilloscope, then calculated the absorption coefficient and the transmittance ratio of the sound. It was found that there is significant relationship between ultrasonic velocity and material properties results show that adding PEG effects on the density then on the absorption of the ultrasonic waves inside the blend samples. Finally applied this blend in various concentrations as additive to imported wood glue and found that increasing the adhesion force after adding comparing with pure. FT-IR test has been made.
Źródło:
World Scientific News; 2015, 21; 12-23
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency Offset Compensation for OFDM Systems Using a Combined Autocorrelation and Wiener Filtering Scheme
Autorzy:
Ramadan Ali, A.
Khanzada, T. J.
Omar, A.
Powiązania:
https://bibliotekanauki.pl/articles/308065.pdf
Data publikacji:
2010
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
channel characterization
frequency offset
OFDM measurement
Wiener filtering
Opis:
One of the orthogonal frequency division multiplexing (OFDM) system disadvantages is its sensitivity to frequency offset and phase noise, which lead to losing the orthogonality between the subcarriers and thereby degrade the system performance. In this paper a joint scheme for frequency offset and pilot-based channel estimation is introduced in which the frequency offset is first estimated using an autocorrelation method, and then is fined further by applying an iterative phase correction by means of pilot-based Wiener filtering method. In order to verify the capability of the estimation algorithm, the scheme has been implemented and tested using a real measurement system in a multipath indoor environment. The results show the algorithm capability of compensating for the frequency offset with different transmission and channel conditions.
Źródło:
Journal of Telecommunications and Information Technology; 2010, 1; 40-47
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study of the mechanical and corrosion properties of ethyl silicate resin applied on low carbon steel
Autorzy:
Ali, M.
Mohmmed, J.H.
Zainulabdeen, A.A.
Powiązania:
https://bibliotekanauki.pl/articles/2175789.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
ethyl silicate resin
polymer coating
low carbon steel
żywica etylokrzemianowa
powłoka polimerowa
stal niskowęglowa
Opis:
Purpose: This work aimed at evaluating the properties of the ethyl silicate-based coating that can be applied on low carbon steel. Design/methodology/approach: Two mixture ratio types (2:1, and 3:2) of resin and hardener respectively were used to prepared two specimen models (A and B). Findings: It found that some mechanical properties (tensile, hardness, and impact strength) of ethyl silicate resin were evaluated according to standard criteria. Research limitations/implications: The effect of heat treatments at various temperatures (100, 150, and 200°C) and holding at different times (10, 20 & 30) min on hardness was investigated. Practical implications: Moreover, an open circuit potential corrosion test with a solution of 3.5% Sodium Chloride at room temperature and 60°C was used to determine the corrosion resistance of low carbon steel specimens coated with the two mixture types. Originality/value: The effects of mixture ratios (for resin and hardener) and heat treatment conditions on properties of ethyl silicate-based coating were studied. From obtained results, acceptable values of tensile, hardness, and toughness were recorded. Increasing heat treatment temperature and holding time leads to enhance hardness for both model types. An open circuit potential (OCP) tests show that there is an enhancement of protective properties of ethyl silicate coatings with mixture type B in comparison with type A was achieved. Generally, the results indicate that specimen model B has higher properties as compared with specimen model A.
Źródło:
Archives of Materials Science and Engineering; 2021, 108, 2; 68--74
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical properties and microstructure of alkali activated mortar containing unexpanded clay
Autorzy:
Nasser, I.F.
Ali, M.A.
Kadhim, M.J.
Powiązania:
https://bibliotekanauki.pl/articles/2201132.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
alkali-activated mortar
pozzolan
unexpanded clay
flexural toughness
scanning electron microscope
thermal insulation
pucolana
glina nie spulchniona
wytrzymałość na zginanie
skaningowy mikroskop elektronowy
izolacja termiczna
Opis:
Purpose: In building constructions, due to the decrease of local raw materials and for sustainability purpose, beside the need of light pieces to be used in roofing and false ceiling; an alkali-activated mortar is the new development where pozzolanic material is used instead of cement and activated by an alkaline solution. Therefore, in this research, alkali-activated mortar containing unexpanded clay as a fine aggregate with a dry density of 1652 kg/m3, compressive strength of 3.2 MPa, and thermal conductivity of 0.4 (W/m.K) was produced ,also boards were performed in a dimension of 305×152×12 mm as to use them in false ceiling, and reinforced with 0.25 and 0.5% steel fibre to improve their toughness by 370.8% and 1146.1% compared with reference boards, which made them good choice to used them in roofing and secondary ceiling. Design/methodology/approach: For preparation of alkali-activated mortar, low calcium fly ash (FA) was used as a source binder material. In addition, super-plasticizer and unexpanded clay as a fine aggregate (produce from the crushed artificial aggregate) in the ratio of 1:2.75 fly ash/fine aggregate. The paste was prepared by mixing fly ash with an alkali silicate solution, in a solid-to-liquid ratio of 0.4. Alkali silicate activator was prepared by mixing the NaOH and Na2SiO3 solutions at the mass ratios of 2.5. The concentrations of the NaOH was the same molarity of (14M).To improve the mechanical properties of the reference mortar mixture ,steel fibre with 0.25 and 0.5% content were added to the mix .The specimens were tested for water absorption, dry density, compressive strength, flexural strengths, flexural toughness, and thermal conductivity, in addition to the Scanning Electron Microscope test (SEM) for all mortar mixes. Alkali-activated mortar boards with (305×152×12 mm) were prepared and tested for flexural strength and toughness. Findings: The results indicated that the modulus of rupture for mortar boards reinforced with 0.25 and 0.5% steel fibre exhibits an increase of (3.68-12.10)%. In comparison, the toughness is increased by about 370.8% and 1146.1%, respectively, as compared with the reference mortar (without fibre) which made them resistance to accident, in addition to use them in roofing due to their thermal insulation. Research limitations/implications: Further research is needed to make a similar board using another sustainable material. We can examine the thermal insulation that we can get from these board, especially in the building in Iraq which the weather faces high temperatures. Practical implications: There is a by-product that we could get from the electricity station in Iraq. We must study how we get rid of it. Originality/value: This paper investigate how to produce a new light board using artificial aggregate made from unexpanded clay, which has many benefits in building insulation roofing.
Źródło:
Archives of Materials Science and Engineering; 2022, 113, 2; 56--68
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Implementation of Analytic Hierarchy Process (AHP) decision ma king framework for building maintenance procurement selection: Case study of Malaysian public universities
Zastosowanie platformy programistycznej wspomagającej podejmowanie decyzji, opartej na procesie hierarchii analitycznej (AHP) w postępowaniu przetargowym na utrzymanie budynków. Przypadek malezyjskich uczelni publicznych
Autorzy:
Chua, S. J. L.
Ali, A. S.
Alias, A. B.
Powiązania:
https://bibliotekanauki.pl/articles/301561.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
analytic hierarchy process (AHP)
building maintenance management
procurement strategy alternative
procurement selection criteria
public university
proces hierarchii analitycznej
zarządzanie utrzymaniem budynków
alternatywna strategia przetargowa
kryteria wyboru zamówienia
uczelnia publiczna
Opis:
In this paper, the proposed Analytic Hierarchy Process (AHP) based decision making framework was implemented and validated for its capability, applicability and validity in assisting building maintenance personnel to select the most appropriate procurement method. The decision making framework was developed based on AHP technique and principles. Expert Choice Software was employed as the development tool where the shortlisted criteria and alternatives were integrated within the framework. The validation process was carried out through a structured interview with nine public universities selected. The evaluations revealed that majority of the interviewees perceived that the framework developed was good (65%) and excellent (21%) in terms of capability, applicability and validity. The proposed decision making framework introduced expected to be a useful tool for maintenance organization that can assist them in decision making on selecting the most appropriate procurement method.
W niniejszej pracy przedstawiono platformę programistyczną wspomagającą podejmowanie decyzji opartą na procesie hierarchii analitycznej (AHP). Po wdrożeniu zaproponowanegoframeworku, weryfikowano jego wydajność, przydatność oraz wiarygodność jako narzędzia wspierającego pracowników utrzymania budynku przy wyborze najodpowiedniejszej metody przetargowej. Platformę opracowano w oparciu o technikę i zasady AHP. Jako narzędzia programistycznego użyto Expert Choice Software, za pomocą którego integrowano z frameworkiem wybrane kryteria i alternatywy. Weryfikację przeprowadzono na podstawie strukturalizowanego wywiadu z wybranymi dziewięcioma uczelniami publicznymi. Otrzymane oceny wykazały, że większość badanych postrzegało opracowaną platformę jako dobrą (65%) lub doskonałą (21%) pod względem wydajności, przydatności i wiarygodności. Przewiduje się, że proponowany framework wspomagający podejmowanie decyzji będzie stanowić użyteczne narzędzie doboru odpowiednich metod przetargowych dla instytucji zajmujących się obsługą techniczną.
Źródło:
Eksploatacja i Niezawodność; 2015, 17, 1; 7-18
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An analytical study on organizational creativity : implications for management
Badania analityczne kreatywności organizacyjnej i kreatywnego podejścia do pracy : implikacje dla kreatywności zarządzania
Autorzy:
Sirkova, M.
Ali Taha, V.
Ferencova, M.
Safarik, P. J.
Powiązania:
https://bibliotekanauki.pl/articles/405664.pdf
Data publikacji:
2014
Wydawca:
Politechnika Częstochowska
Tematy:
creativity
creative approach
management
organization
workplace
kreatywność
twórcze podejście
zarządzanie
organizacja
miejsce pracy
Opis:
In dynamically and unpredictably changing environment becomes creativity a key factor of the success of businesses and organizations because it affects the development of innovation and ingenuity, and consequently the business success and profit. The paper analyses the creativity of employees at work. Primary data collection was conducted through questionnaire survey among employees (mostly managers) working in Prešov region. The research was conducted on a sample of 118 respondents from Prešov district in Slovakia. To evaluate the data and hypotheses was used statistical program STATISTIC using the Pearson correlation coefficient (r).
W dynamicznie i nieprzewidywalnie zmieniającym się środowisku kreatywność staje się kluczowym czynnikiem sukcesu przedsiębiorstw i organizacji, ponieważ ma wpływ na rozwój innowacyjności i pomysłowości, a w konsekwencji na sukces w biznesie i zysk. Niniejszy artykuł analizuje kreatywność pracowników w miejscu pracy. Zbieranie podstawowych danych zostało przeprowadzone w formie badania ankietowego wśród pracowników (głównie menedżerów) pracujących w regionie Preszów. Badania przeprowadzono na próbie 118 respondentów z powiatu Preszów na Słowacji. Do oceny danych i hipotezy użyto programu statystycznego STATISTICA wykorzystując współczynnik korelacji Pearsona (r).
Źródło:
Polish Journal of Management Studies; 2014, 10, 2; 179-187
2081-7452
Pojawia się w:
Polish Journal of Management Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Buckling and bending properties of aluminium plate with multiple cracks
Autorzy:
Mohmmed, J. H.
Mahmood, N. Y.
Ali, M.
Zainulabdeen, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/1818485.pdf
Data publikacji:
2020
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
buckling stability
bending strength
crack
aluminium plate
ANSYS package
stabilność wyboczeniowa
wytrzymałość na zginanie
pęknięcie
płyta aluminiowa
pakiet ANSYS
Opis:
Purpose: In this paper, the bending strength and buckling stability of (AA 7075-T6) aluminium plate weakened by many transverse cracks, which located at different positions, subjected to concentrated loads applied at the ends were analysed. Design/methodology/approach: Numerical modelling and calculation by the finite element method (ANSYS Package), for the critical load of bending and compression panel were estimated. Findings: It found that the variation of the critical stress in bending and buckling is proportional to the crack conditions (no. of crack and location). In general, the critical load in bending and buckling decreases with increasing the crack number in structure. Research limitations/implications: For both bending and buckling, two transverse cracks on one face of plate is more stable than two transverse cracks on opposite faces. Practical implications: In addition, many experimental tests were carried out by using an INSTRON test machine to obtain the buckling critical loads, where the experimental results were compared with the ones of the finite element method. Furthermore, bending strength was calculated theoretically for the cracked panel. Originality/value: Comparison between the experimental and numerical (FE based model) data and between the theoretical and nu-merical (FE based model) data for buckling and bending strength respectively indicate the precise and the simplicity of the developed models to determine the critical loads in such cases.
Źródło:
Archives of Materials Science and Engineering; 2020, 106, 2; 49--58
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of Crosstalk into High Resistivity Silicon Substrate on the RF Performance of SOI MOSFET
Autorzy:
Ali, K. B.
Neve, C. R.
Gharsallah, A.
Raskin, J. P.
Powiązania:
https://bibliotekanauki.pl/articles/308378.pdf
Data publikacji:
2010
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
crosstalk
high resistivity Si
mixing products
passivation layer
polysilicon
Opis:
Crosstalk propagation through silicon substrate is a serious limiting factor on the performance of the RF devices and circuits. In this work, substrate crosstalk into high resistivity silicon substrate is experimentally analyzed and the impact on the RF behavior of silicon-on-insulator (SOI) MOS transistors is discussed. The injection of a 10 V peak-to-peak single tone noise signal at a frequency of 3 MHz ( fnoise) generates two sideband tones of ?56 dBm separated by fnoise from the RF output signal of a partially depleted SOI MOSFET at 1 GHz and 4.1 dBm. The efficiency of the introduction of a trap-rich polysilicon layer located underneath the buried oxide (BOX) of the high resistivity (HR) SOI wafer in the reduction of the sideband noise tones is demonstrated. An equivalent circuit to model and analyze the generation of these sideband noise tones is proposed.
Źródło:
Journal of Telecommunications and Information Technology; 2010, 4; 93-100
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation and selection process of suppliers through analytical framework: an emprical evidence of evaluation tool
Autorzy:
Imeri, S.
Shahzad, K.
Takala, J.
Liu, Y
Sillanpää, I.
Ali, T.
Powiązania:
https://bibliotekanauki.pl/articles/407383.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
supplier evaluation
supplier performance management
supplier selection model
principal component analysis
supply chain management
Opis:
The supplier selection process is very important to companies as selecting the right suppliers that fit companies strategy needs brings drastic savings. Therefore, this paper seeks to address the key area of supplies evaluation from the supplier review perspective. The purpose was to identify the most important criteria for suppliers’ evaluation and develop evaluation tool based on surveyed criteria. The research was conducted through structured questionnaire and the sample focused on small to medium sized companies (SMEs) in Greece. In total eighty companies participated in the survey answering the full questionnaire which consisted of questions whether these companies utilize some suppliers’ evaluation criteria and what criteria if any is applied. The main statistical instrument used in the study is Principal Component Analysis (PCA). Thus, the research has shown that the main criteria are: the attitude of the vendor towards the customer, supplier delivery time, product quality and price. Conclusions are made on the suitability and usefulness of suppliers’ evaluation criteria and in way they are applied in enterprises.
Źródło:
Management and Production Engineering Review; 2015, 6, 3; 10-20
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication of a Spherical Titanium Powder by Combined Combustion Synthesis and DC Plasma Treatment
Autorzy:
Choi, S. H.
Ali, B.
Hyun, S. K.
Sim, J. J.
Choi, W. J.
Joo, W.
Lim, J. H.
Lee, Y. J.
Kim, T. S.
Park, K. T.
Powiązania:
https://bibliotekanauki.pl/articles/356067.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
combustion synthesis
DC plasma treatment
titanium powder
3D printing process
combustion parameters
Opis:
Combustion synthesis is capable of producing many types of refractory and ceramic materials, as well as metals, with a relatively lower cost and shorter time frame than other solid state synthetic techniques. TiO2 with Mg as reductant were dry mixed and hand compacted into a 60 mm diameter mold and then combusted under an Ar atmosphere. Depending on the reaction parameters (Mg concentration 2 ≤ α ≤ 4), the thermocouples registered temperatures between 1160°C and 1710°C . 3 mol of Mg gave the optimum results with combustion temperature (Tc) and combustion velocity (Uc) values of 1372°C and 0.26 cm/s respectively. Furthermore, this ratio also had the lowest oxygen concentration in this study (0.8 wt%). After combustion, DC plasma treatment was carried out to spheroidize the Ti powder for use in 3D printing. The characterization of the final product was performed using X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and N/O analysis.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1057-1062
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of LMX as Mediator in Procedural Justice – Organizational Citizenship Behavior Relationship
Autorzy:
Ishaq, Muhammad Ishtiaq
Nazia, Munazer Hussain
Nawaz, Muhammad Musarrat
Asim, Ali Ijaz
Cheema, Luqman J.
Powiązania:
https://bibliotekanauki.pl/articles/45636411.pdf
Data publikacji:
2012-09-30
Wydawca:
Wydawnictwo Adam Marszałek
Tematy:
faculty
higher education
LMX
OCB
Pakistan
procedural justice
universities
Opis:
Scant literature is available on procedural justice – organizational citizenship behaviour (OCB) via mediating role of leader-member exchange (LMX) in higher education context especially in Asian countries like Pakistan. For this purpose, data was collected from 452 permanent and contractual teaching faculty serving in different positions at private and public sector degree awarding institutes / universities accredited by the Higher Education Commission (HEC) of Pakistan. Mediated regression analysis, as proposed by Baron and Kenny (1986), was employed to address the research hypothesis. Results showed that LMX fully mediates the relationship of procedural justice OCB. Implications for future researchers and academic administrators are presented.
Źródło:
The New Educational Review; 2012, 29; 202-211
1732-6729
Pojawia się w:
The New Educational Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SYNTHESIS, AND EVALUATION OF COUMARIN HYBRIDS AS ANTIMYCOBACTERIAL AGENTS
Autorzy:
Hassan, Mohd Z.
ALSAYARI, ABDULRHMAN
OSMAN, HASNAH
ALI, MOHAMED A.
MUHSINAH, ABDULLATIF B.
AHSAN, MOHAMED J.
Powiązania:
https://bibliotekanauki.pl/articles/895509.pdf
Data publikacji:
2019-12-29
Wydawca:
Polskie Towarzystwo Farmaceutyczne
Tematy:
cytotoxicity
Coumarin
TB
Thiazolopyrimidine
HTS
antimycobacterial
Opis:
A series of twelve hybrid coumarin analogues were synthesized and screened through HTS for their antimycobacterial activity against Mtb H37Rv. The hybrid molecules were efficiently synthesized by the reactions of 3-(bromoacetyl)coumarin with Biginelli products 2-mercapto-6-oxo-4-aryl-1,6-dihydropyrimidine-5-carbonitriles. Of the resulting twelve hybrids, the two compounds 7-(2,4-dichlorophenyl)-5-oxo-3-(2-oxo-2H-chromen-3-yl)-5H-thiazolo[3,2-a] pyrimidine-6-carbonitrile (3d) and 7-(4-nitrophenyl)-5-oxo-3-(2-oxo-2H-chromen-3-yl)-5H-thiazolo[3,2-a]pyrimidine-6-carbonitrile (3f) showed excellent antimycobacterial activity against Mtb (EC50 3.19 & 7.91 µM, respectively) and low cytotoxicity against the VERO cell line (IC50 > 62.5 µg/mL).
Źródło:
Acta Poloniae Pharmaceutica - Drug Research; 2019, 76, 6; 1029-1036
0001-6837
2353-5288
Pojawia się w:
Acta Poloniae Pharmaceutica - Drug Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Antibacterial Activities of Some Transition Metal Schiff Base Complexes
Autorzy:
Islam, M.N.
Shahriar, S.M.S.
Islam, M.K.
Jesmin, M.
Ali, M.M.
Khanam, J.A.
Powiązania:
https://bibliotekanauki.pl/articles/411780.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
antibacterial activity
Schiff base transition metal complexes
minimum inhibitory concentration
Brine shrimp lethality
Opis:
A new series of four transition metal complexes of a Schiff base derived from salicylaldehyde and glycine, viz. [N-salicylidene glycinato diaqua cobalt (II) dimer] (SGCo)2, [N- salicylideneglycinato-di-aqua-nickel(ll)dimer] (SGN)2, [N-salicylideneglycinato-aqua-copper(II)] (SGC) and [N-salicylidene glycinato diaqua zinc(II) dimer] (SGZ)2 have been synthesized and characterized through a rapid, simple, and efficient methodology in excellent yield. These compounds were screened for in vitro antibacterial activities against six pathogenic bacteria, such as Shigella sonnei, Escherichia coli, Bacilus subtilis, Sarcina lutea, Staphylococcus aureus and Pseudomonas arioginosa. The antibacterial activity was determined by the disc diffusion method using DMSO as solvent. The results indicate that (SGC) compound exhibit a significant antibacterial activity, depending on the bacterial strain and (SGCo)2, (SGN)2 and (SGZ)2 compounds show a moderate sensitivity even with higher doses. All these compounds were found to possess cytotoxic effect.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 5; 12-20
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The efficiency of some fungi species in wastewater treatment
Autorzy:
Kadhim, Nuha F.
Mohammed, Wathiq J.
Al Hussaini, Ibtihal M.
Al-Saily, Hala M.N.
Ali, Rasha N.
Powiązania:
https://bibliotekanauki.pl/articles/1841944.pdf
Data publikacji:
2021
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
bioremediation
fungi
nitrite
phosphate
wastewater
Opis:
Using microorganisms in eliminating or reducing the impacts of harmful remnants is very ancient manner. The current study was conducted to explore the potential of utilizing some fungi species that isolated from the main sewage treatment plant in Al-Muamirah area, Babylon-Iraq, in reducing some pollutants. Six fungi taxa Aspergillus flavus, A. niger, A. terrues, Candida albicans, C. krusei, and Penicillium digitatum were identified before any treatment process, whereas only four fungi species A. flavus 20%, A. niger 20%, A. terrues 10%, and P. digitatum 18% were recognized after completing the physical and chemical treatment stages. Only three taxa A. niger, A. terrues, and P. digitatum were employed to reveal their capability in treating the sewage water, which represent the biological treatment stage as the final step of the treatment processes. The results showed a considerable capability of these fungi species in decreasing many variables values such as pH, total soluble solids (TSS), electrical conductivity (EC), salinity, total alkalinity, chlorides, nitrite, and phosphate. Where, slightly low reduction was detected in TSS value in all experiments (1.1–5.9%), similarly, both EC and salinity which were decreased with low ratios (6.6%, 3.9%, respectively). Taxon A. terrues exhibited high ability in reducing the total alkalinity and chloride ions in the treated water (30.9%, 43%, respectively) in comparison with the other two fungi species. Furthermore, all three fungi species were posed high capability in decreasing nutrients, where both nitrite and phosphate ions were highly reduced (87–97% and 22.8–32.1%, respectively). Based on these findings, we suggest using other microorganisms and exploring their capacity in removing the pollutants, and revealing the ability of the above fungi taxa in removing other pollutants.
Źródło:
Journal of Water and Land Development; 2021, 50; 248-254
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exhaled breath malondialdehyde, spirometric results and dust exposure assessment in ceramics production workers
Autorzy:
Sakhvidi, Mohammad J.
Biabani Ardekani, Javad
Firoozichahak, Ali
Zavarreza, Javad
Hajaghazade, Mohammad
Mostaghaci, Mehrdad
Mehrparvar, Amirhooshang
Barkhordari, Abolfazl
Powiązania:
https://bibliotekanauki.pl/articles/2177001.pdf
Data publikacji:
2015-02-24
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
Oxidative stress
occupational exposures
spirometry
breath condensate
malondialdehyde
Opis:
Introduction The study aimed at measuring exhaled breath malondialdehyde (EBC-MDA) in workers exposed to dust containing silica and at its comparison with the non-exposed control group. Material and methods The cross sectional, case-control study (N = 50) was performed in a tile and ceramics production factory in Yazd, Iran. EBC-MDA was quantified in exhaled breath of the participants by a lab made breath sampler. Exposure intensity was measured according to the NIOSH 0600 method in selected homogeneous exposure groups. Additionally, spirometry test was conducted to investigate a correlation between EBC-MDA and spirometric findings in the exposed workers. Results There was no difference in the observed exposure intensities of silica containing dust in different units. However, “coating preparation” was the unit with the highest concentration of dust. Although, the level of EBC-MDA in the cases was slightly higher than in the controls, the difference was not statistically significant (U = 252, p = 0.464). A significant and positive correlation was found between dust exposure intensity in working units and the measured EBC-MDA of workers (r = 0.467, N = 25, p = 0.027). There were also no statistically significant differences among job categories in the exposed group for the values of FEV1% (F(3, 44) = 0.656, p = 0.584), FVC% (F(3, 44) = 1.417, p = 0.172), and FEV1/FVC% (F(3, 44) = 1.929, p = 0.139). Conclusions The results showed a significant correlation between respirable dust exposure intensity and the level of EBC-MDA of the exposed subjects. However, our results did not show a significant correlation between lung function decreases and EBC-MDA.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2015, 28, 1; 81-89
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reaction Kinetics and Morphological Study of TiNb2O7 Synthesized by Solid-State Reaction
Autorzy:
Choi, S. H.
Ali, B.
Choi, K. S.
Hyun, S. K.
Sim, J. J.
Choi, W. J.
Joo, W.
Lim, J. H.
Lee, T. H.
Kim, T. S.
Park, K. T.
Powiązania:
https://bibliotekanauki.pl/articles/355326.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solid state reaction
kinetic analysis
quantitative phase analysis
TiNb2O7 synthesis
Opis:
Although TiNb2O7 is regarded as a material with high application potential in lithium-ion batteries (LIBs) and solid-oxide fuel cells (SOFCs), it has been difficult to find suitable cost-effective conditions for synthesizing it on a commercial scale. In this study, TiNb2O7 compounds were synthesized by a solid state synthesis process. For stoichiometrically precise synthesis of the TiNb2O7 phase, the starting materials, TiO2 and Nb2O5 were taken in a 1:1 molar ratio. Activation energy and reaction kinetics of the system were investigated at various synthesis temperatures (800,1000,1200, and 1400°C) and for various holding durations (1,5,10, and 20 h). Furthermore, change in the product morphology and particle size distribution were also evaluated as a function of synthesis temperature and duration. Additionally, quantitative phase analysis was conducted using the Rietveld refinement method. It was found that increases in the synthesis temperature and holding time lead to increase in the mean particle size from 1 to 4.5 μm. The reaction rate constant for the synthesis reaction was also calculated.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1051-1056
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
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